Consider two frames of reference, S and S', the first one being fixed to the ground and the second one fixed to a train moving at 5.00 m//s with respect to the ground (figure) A block of mass 4.00 kg, initially at rest with respect to S', is acted upon by a 14.0 N force for 3.00s in the positive x direction. Neglect friction.
According to an observer in S,

Options

A. Work energy theorem cannot be applied in frame S'
B. Work energy theorem is derived from Newton is second law it is valid in all inertial reference frames.
C. Work done by force is same in both the frames.
D. Change in kinetic energy of both the blocks is independent of reference frames S and S'

Answer

B